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See detailOpen Data and AquaCrop : sorghum yield estimates in support to food security in Niger
Mohamed Sallah, Abdoul-Hamid ULiege; Wellens, Joost ULiege; Garba, Issa et al

Poster (2019, September 20)

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See detailBatch-processing of AquaCrop plug-in for rainfed maize using satellite derived Fractional Vegetation Cover data
Mohamed Sallah, Abdoul-Hamid ULiege; Tychon, Bernard ULiege; Piccard, Isabelle et al

in Agricultural Water Management (2019), 217(346-355),

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See detailImproving fodder biomass modeling in the sahelian zone of Niger using the multiple linear regression method
Garba, Issa ULiege; Djaby, Bakary ULiege; Salifou, Illa et al

in International Journal for Research in Applied Science and Engineering Technology (2017), 5(5), 1627-1639

This study was carried out in Niger and aims to propose an improved fodder biomass estimate model using the Multiple Linear Regression (MRM) method. The work was carried out with measurements of ... [more ▼]

This study was carried out in Niger and aims to propose an improved fodder biomass estimate model using the Multiple Linear Regression (MRM) method. The work was carried out with measurements of herbaceous mass (in situ) made from 2001 to 2012 by the Ministry of Livestock and Animal Industry of Niger MEIA); rainfalls observed by the Niger Meteorological Office and the meteorological variables from the European Center for Medium - Range Weather Forecasts (ECMWF), processed in AgrometShell (AMS) to derive the agro- meteorological variables; the SPOT VEGETATION NDVI satellite images processed in the "Vegetation Analysis in Space and Time" (VAST) program to derive biophysical variables from the annual NDVI decadal series and finally the estimated rainfall known as RFE from the American institution "Famine Early Warning Systems Network "(FEWSNET) for the calculation of annual rainfall totals. The model was performed by multiple linear regressions with the ascending step – by - step procedure for the selection of variables based on the adjusted R² and the RMSE. Leave One Out Cross Validation (LOOICV) was used to calculate the validation R² and a systematic diagnosis of residues to better characterize the model. Throughout the (national) study area, MRM performed an adjusted R² of 0.68 and a RMSE of 282 kg. Ha-1, the difference between the RMSE of the calibration and that of the validation is 3.72 kg.ha-1. However, it is necessary to continue this research with other indices such as LAI and FAPAR and EVI. Also, it would be interesting to explore ways such as: taking into account the foliage of the trees, adjusting the metrics to the phenology of the herbaceous plants, and those of the woody ones. This work will improve the quality of information used to plan development actions in favor of Niger society in order to protect it against pastoral crises. [less ▲]

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See detailValidation of herbaceous biomass assessment model for sahelian rangelands (biomasah) in Niger.
Garba, Issa ULiege; Salifou, Illa; Djaby, Bakary ULiege et al

in International Journal of Current Research (2017), 9(4), 48992-48999

This study was carried out in the pastoral zone of Niger with the aim of validating outputs of the BIOMASAH model developed by the AGRHYMET Regional Centre (ARC) relative to real data collected over the ... [more ▼]

This study was carried out in the pastoral zone of Niger with the aim of validating outputs of the BIOMASAH model developed by the AGRHYMET Regional Centre (ARC) relative to real data collected over the 2001-2011 period by the Ministry Livestock and Animal Industries (MEIA) of Niger. We used parametric tests (t-tests) and nonparametric tests (Wilcoxon and sign tests) for mean comparisons. A correlation analysis was performed by calculating Pearson’s r, Spearman’s ρ, Kendall’s T and Hoeffding’s D correlation coefficients. The results showed that the BIOMASAH model generally overestimated biomass (983.17 vs. 591.17 kg/ha) with a highly significant difference relative to the field findings (P <.0001). Pearson’s r (0.15), Spearman’sρ (0.22) Kendall’s T (0.13) and Hoeffding’s D (0.1) correlation coefficients were low but highly significant (p <.0001). Grazing pressure and spatiotemporal variability of rainfall helped explain the noted differences. [less ▲]

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See detailMapping of zones at risk (ZAR) in West Africaby using NGI, VCI and SNDVI from the e-station.
Garba, Issa ULiege; Salifou, Illa; Sallah, Abdoul Hamid et al

in International Journal of Advanced Research (2017), 5(4), 1376-1386

This work is carried out at the AGRHYMET Regional Centre (ARC)-CILSS as part of the African Monitoring of Environment for Sustainable Development (AMESD) project. The analysis protocol has been improved ... [more ▼]

This work is carried out at the AGRHYMET Regional Centre (ARC)-CILSS as part of the African Monitoring of Environment for Sustainable Development (AMESD) project. The analysis protocol has been improved under the Monitoring of Environment for Security in Africa (MESA) project. The MESA Project has been designed on the achievements of AMESD; its overall objective is to provide African countries with access to Earth Observation data for environmental monitoring and sustainable development. The specific objective of this study is to develop an operational analysis protocol for vegetation monitoring in general and especially for crops and pastures. Three vegetation indices were used: Vegetation Condition Index (VCI), Normalized Growth Index (NGI) and Standardized Normalized Difference Vegetation Index (SNDVI). The analysis of these drought indices is based on taking into account the agro-climatic characteristics of the Sahelian region, the comparison of the NGI profile (per administrative unit) from year X (in progress) to the maximum NGI profiles, minimum and average of the time series data (1998 to year x-1) and evidence convergence. Six years of application of the method and validation actions carried out concluded that it is possible to determine the zones at risk (ZAR) in order to anticipate food crises. [less ▲]

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See detailPerformance of similarity analysis in the estimation of forage yields in the Sahelian zone of Niger
Garba, Issa ULiege; Salifou, Illa; Djaby, Bakary ULiege et al

in International Journal of Scientific and Engineering Research (2017), 8(2), 1072-1088

The study aims to test the performance of similarity analysis in herbaceous fodder biomass estimate in the Nigerian pastoral zone, in a context of insecurity and precipitation spatiotemporal variability ... [more ▼]

The study aims to test the performance of similarity analysis in herbaceous fodder biomass estimate in the Nigerian pastoral zone, in a context of insecurity and precipitation spatiotemporal variability. It is carried out on the time series of NDVI decadal images of SPOT VEGETATION for the period from 2001 to 2012 and on fodder biomasses measured in situ during the same period. Similarity analysis compares NDVI seasonal patterns to detect similar years using three criteria: the RMSE (Root Mean squared error), the MAD (Mean absolute Deviation), and R². Exploratory statistical analyzes with bootstrap are carried out to better characterize the observations resulting from the simulation. Moreover, the analysis of the parametric and non-parametric correlations is carried out to evaluate the level of link between the simulated data and the real data. The t test and the Wilcoxon test are then carried out in order to compare the means of the actual biomasses with those obtained by the similarity analysis. At the local level, the results indicate that the R² is more efficient than the RMSE and the MAD which have almost the same performances. The results of the similarity calculated with R² can be used as a proxy to the herbaceous phytomass measured in situ, as there is no significant difference between the simulated mean and the mean measured at the 1% threshold. On the other hand, the results of the similarity calculated with the RMSE and the MAD are not exploitable. Parametric and nonparametric correlations are all significant at the 1% threshold. However, the R² are low and vary between 0.32 and 0.45. It therefore seems necessary to continue the research, as numerous studies have revealed very good links between certain indices like the FAPAR, the EVI and the LAI and the aerial phytomasse. [less ▲]

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See detailEvolution récente des extrêmes pluviométriques au Niger (1950-2014)
Ozer, Pierre ULiege; Laminou Manzo; Tidjani, Adamou Didier et al

in Geo-Eco-Trop: Revue Internationale de Géologie, de Géographie et d'Écologie Tropicales (2017), 41(3), 375-384

L’Afrique de l’Ouest est la région du monde qui connait le déficit pluviométrique le plus important. Le Niger, l’un des pays les plus pauvres du monde, est hautement dépendant des variations ... [more ▼]

L’Afrique de l’Ouest est la région du monde qui connait le déficit pluviométrique le plus important. Le Niger, l’un des pays les plus pauvres du monde, est hautement dépendant des variations pluviométriques dans un contexte de réchauffement climatique dont les conséquences semblent être défavorables dans les décennies à venir. Sur base des données pluviométriques quotidiennes de 37 stations nigériennes, cet article analyse l’évolution des précipitations au travers de onze indices entre 1950 et 2014. Après une sévère sécheresse de trois décennies qui est individualisée de 1968 à 1997, il apparait que si un retour à une pluviométrie moyenne annuelle subnormale est observé depuis 1998, il n’en est rien pour d’autres indices vitaux pour le monde rural dépendant de la bonne distribution des précipitations durant la saison des pluies. En effet, les jours secs consécutifs ont considérablement augmenté et les jours humides consécutifs se sont réduits. Il en va de même pour les jours pluvieux. Dans le même temps, la proportion de la précipitation maximale quotidienne dans le total pluviométrique annuel s’est renforcée au fil du temps et la proportion des précipitations intenses dans le total pluviométrique annuel s’est significativement accentuée au cours des deux dernières décennies [less ▲]

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See detailEvolution récente des extrêmes pluviométriques au Niger (1950-2014)
Ozer, Pierre ULiege; Laminou, Manzo Ousmane; Tidjani, Adamou Didier et al

Conference (2016, September 28)

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See detailDo Agrometeorological Data Improve Optical Satellite-based Estimations of Herbaceous Yield in Sahelian Semi-Arid Ecosystems?
Diouf, Abdoul Aziz ULiege; Hiernaux, Pierre; Brandt, Martin et al

in Remote Sensing (2016), 8

Quantitative estimates of forage availability at the end of the growing season in rangelands are helpful for pastoral livestock managers and for local, national and regional stakeholders in natural ... [more ▼]

Quantitative estimates of forage availability at the end of the growing season in rangelands are helpful for pastoral livestock managers and for local, national and regional stakeholders in natural resource management. For this reason, remote sensing data such as the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) have been widely used to assess Sahelian plant productivity for about 40 years. This study combines traditional FAPAR-based assessments with agrometeorological variables computed by the geospatial water balance program, GeoWRSI, using rainfall and potential evapotranspiration satellite gridded data to estimate the annual herbaceous yield in the semi-arid areas of Senegal. It showed that a machine-learning model combining FAPAR seasonal metrics with various agrometeorological data provided better estimations of the in situ annual herbaceous yield (R² = 0.69; RMSE = 483kg•DM/ha) than models based exclusively on FAPAR metrics (R² = 0.63; RMSE = 550kg•DM/ha) or agrometeorological variables (R² = 0.55; RMSE = 585kg•DM/ha). All the models provided reasonable outputs and showed a decrease in the mean annual yield with increasing latitude, together with an increase in relative inter-annual variation. In particular, the additional use of agrometeorological information mitigated the saturation effects that characterize the plant indices of areas with high plant productivity. In addition, the date of the onset of the growing season derived from smoothed FAPAR seasonal dynamics showed no significant relationship (0.05 p-level) with the annual herbaceous yield across the whole studied area. The date of the onset of rainfall however, was significantly related to the herbaceous yield and its inclusion in fodder biomass models could constitute a significant improvement in forecasting risks of a mass herbaceous deficit at an early stage of the year. [less ▲]

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See detailZonage phénoclimatique et caractérisation des parcours naturels du Sénégal avec les données de télédétection satellitaire
Diouf, Abdoul Aziz ULiege; Faye, G.; Minet, Julien ULiege et al

in XXVIIIème Colloque de l’Association Internationale de Climatologie, Liège 1-5 juillet 2015 (2015, July 02)

Les métriques phénologiques qui expriment certains événements du cycle de vie des plantes, tels que l'émergence, la croissance et la sénescence, principalement liées aux conditions météorologiques et au ... [more ▼]

Les métriques phénologiques qui expriment certains événements du cycle de vie des plantes, tels que l'émergence, la croissance et la sénescence, principalement liées aux conditions météorologiques et au climat, ont été utilisées afin : (i) de déterminer, à travers les parcours naturels du Sénégal, des entités "phénoclimatiques" homogènes ou phénorégions par classification non-supervisée des images de la série temporelle (1999-2013); (ii) d’analyser l’homogénéité des phénorégions en comparant l’évolution interannuelle de l’indice et des quantités de précipitation et (iii) de donner leurs principales caractéristiques biophysiques. Les résultats obtenus montrent que le domaine pastoral sénégalais peut être subdivisé en trois phénorégions à partir de la grande intégrale du NDVIS10 qui donne les entités spatiales les plus homogènes dans lesquelles les paramètres biophysiques comportent une variation latitudinale caractéristique du Sahel [less ▲]

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See detailFodder Biomass Monitoring in Sahelian Rangelands Using Phenological Metrics from FAPAR Time Series
Diouf, Abdoul Aziz ULiege; Brandt, Martin; Verger, Aleixandre et al

in Remote Sensing (2015), 7(9122-9148),

Timely monitoring of plant biomass is critical for the management of forage resources in Sahelian rangelands. The estimation of annual biomass production in the Sahel is based on a simple relationship ... [more ▼]

Timely monitoring of plant biomass is critical for the management of forage resources in Sahelian rangelands. The estimation of annual biomass production in the Sahel is based on a simple relationship between satellite annual Normalized Difference Vegetation Index (NDVI) and in situ biomass data. This study proposes a new methodology using multi-linear models between phenological metrics from the SPOT-VEGETATION time series of Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) and in situ biomass. A model with three variables—large seasonal integral (LINTG), length of growing season, and end of season decreasing rate—performed best (MAE = 605 kg·DM/ha; R2 = 0.68) across Sahelian ecosystems in Senegal (data for the period 1999–2013). A model with annual maximum (PEAK) and start date of season showed similar performances (MAE = 625 kg·DM/ha; R2 = 0.64), allowing a timely estimation of forage availability. The subdivision of the study area in ecoregions increased overall accuracy (MAE = 489.21 kg·DM/ha; R2 = 0.77), indicating that a relation between metrics and ecosystem properties exists. LINTG was the main explanatory variable for woody rangelands with high leaf biomass, whereas for areas dominated by herbaceous vegetation, it was the PEAK metric. The proposed approach outperformed the established biomass NDVI-based product (MAE = 818 kg·DM/ha and R2 = 0.51) and should improve the operational monitoring of forage resources in Sahelian rangelands. [less ▲]

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See detailLIVESTOCK SYSTEMS--TECHNICAL REPORT
Minet, Julien ULiege; Diouf, Abdoul Aziz ULiege; Garba, Issa ULiege et al

Report (2015)

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See detailFonctions d’ajustement pour l’estimation de la production fourragère herbacée des parcours naturels du Sénégal à partir du NDVI s10 de SPOT-vegetation
Diouf, Abdoul Aziz ULiege; Djaby, Bakary ULiege; Diop, Mouhamadou Bamba et al

in XXVIIe Colloque de l’Association Internationale de Climatologie (2014, July 04)

Face à la situation actuelle de changement climatique et ses conséquences sur l’homme et les ressources naturelles, les Systèmes d’Alerte Précoce (SAP) sur le disponible fourrager en zones pastorales ... [more ▼]

Face à la situation actuelle de changement climatique et ses conséquences sur l’homme et les ressources naturelles, les Systèmes d’Alerte Précoce (SAP) sur le disponible fourrager en zones pastorales constituent des stratégies essentielles dans la lutte contre l’insécurité alimentaire, notamment au niveau des pays du Sahel ouest-africains comme le Sénégal. L’évaluation du stock de fourrage s’y effectue habituellement à partir d’une régression linéaire entre les données de biomasse mesurée sur le terrain et l’indice de végétation par différence normalisée (NDVI) issu du satellite SPOT VEGETATION. Mais, compte tenu de la nature non-linéaire de la relation NDVI-biomasse herbacée, cinq autres fonctions d’ajustement sont testées afin de déterminer celles qui traduisent au mieux cette relation.Les données de biomasse ont été collectées au niveau de cinquante-et-un Sites de Contrôle au Sol (SCS) dont trente-six ont servi à la calibration et quinze pour évaluer la précision des modèles. Les variables utilisées sont le NDVI moyen et le NDVI maximum, enregistrés au cours de la saison. Les résultats obtenus montrent que les modèles Exponentiel et Puissance sont les plus cohérents et précis pour l’estimation de la biomasse herbacée à partir du NDVI. Toutefois, cette approche empirique par régression simple reste globalement imprécise pour l’évaluation de la biomasse herbacée au Sénégal vu les valeurs relativement élevées du RMSE qui varient entre 324,07 et 858 kg/ha selon l’année. [less ▲]

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See detailEvolution récente des extrêmes pluviométriques en Mauritanie (1933-2010)
Ozer, Pierre ULiege; Hountondji, Yvon-Carmen ULiege; Gassani, Jean ULiege et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du 27e Colloque International de l'Association Internationale de Climatologie (2014)

Un ensemble d’indicateurs a été compilé pour vérifier si la fréquence et/ou l’intensité des précipitations a significativement évolué au cours des dernières décennies dans la République Islamique de ... [more ▼]

Un ensemble d’indicateurs a été compilé pour vérifier si la fréquence et/ou l’intensité des précipitations a significativement évolué au cours des dernières décennies dans la République Islamique de Mauritanie. Cette étude s’appuie sur des indices nationaux basés les séries quotidiennes de précipitations de neuf stations synoptiques qui couvrent la période 1933-2010. L’analyse des précipitations a été réalisée en calculant annuellement treize indices pluviométriques : le total pluviométrique (PTOT), le nombre total de jours humides (précipitations ≥1 mm, JP), la lame d’eau moyenne précipitée par jour humide (Simple day intensity index, SDII), la pluviométrie maximale enregistrée sur 1 jour (Px1J), la fréquence des événements pluviométriques ≥ 10 mm (P10), ≥ 20 mm (P20), intenses (P95) et extrêmes (P99). Le poids relatif des cinq derniers indices dans le total pluviométrique annuel étant également apprécié. Les résultats montrent que les indices PTOT, JP, P10 et P20 présentent une tendance à la baisse significative sur la période 1933-2010. Dans le même temps, la fréquence des précipitations intenses et extrêmes évolue peu. De facto, la lame d’eau moyenne précipitée par jour humide (SDII) augmente de manière significative. Les résultats obtenus vont dans le sens des conclusions du Groupe d’expert intergouvernemental sur l’évolution du climat (Giec) à l’échelle globale, à savoir des précipitations extrêmes inchangées dans un contexte global de dessiccation. Selon de nombreux modèles, la dégradation pluviométrique pourrait s’amplifier dans les décennies à venir. Dès lors, des stratégies d’adaptation transfrontalières devraient être envisagées d’urgence car le processus de réchauffement de la planète n'est pas susceptible de diminuer dans les prochaines décennies. [less ▲]

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See detailThe Agrometeorological crop yield forecasting System of Armenia - User Manual - December 2013
Tychon, Bernard ULiege; Denis, Antoine ULiege; Djaby, Bakary ULiege et al

Learning material (2013)

« This document was produced under the Agrometeorological component of the “EC/FAO Programme on Information Systems to Improve Food Security Decision-Making in ENP East Area” in Armenia. The objective of ... [more ▼]

« This document was produced under the Agrometeorological component of the “EC/FAO Programme on Information Systems to Improve Food Security Decision-Making in ENP East Area” in Armenia. The objective of the Programme in Armenia is to support government’s priorities to reduce food insecurity and poverty by improving the quality and sharing of information across institutions, and promoting evidence-based analyses and assessments. This User Manual of Crop Yield Forecasting System used in Armenia may be used as a reference document for the future calculation of yield forecasts that HYDROMET will use in the coming years. [less ▲]

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See detailÉVOLUTION CLIMATIQUE, PERCEPTION ET ADAPTATION DES COMMUNAUTES RURALES DU PLATEAU D’ABOMEY (BENIN)
Ozer, Pierre ULiege; Hountondji, Yvon-Carmen ULiege; Ahomadegbe, Mathias et al

in Boko, Michel; Vissin, Expédit W.; Afouda, Fulgence (Eds.) CLIMAT, AGRICULTURE & RESSOURCES EN EAU d'hier à demain (2013, September)

West Africa is extremely vulnerable to climate change. This paper first analyses recent trends in extreme rainfall and temperatures recorded at six synoptic stations in Benin. Results show that rainfall ... [more ▼]

West Africa is extremely vulnerable to climate change. This paper first analyses recent trends in extreme rainfall and temperatures recorded at six synoptic stations in Benin. Results show that rainfall is declining while temperatures are increasing significantly. Cold nights (1st TMin percentile) are decreasing very significantly while hot days (99th TMax percentile) are increasing very significantly. No trend is observed in the frequency of extreme rainfall events. Then, rural populations of the plateau of Abomey were interviewed about their perception of climatic risks. They highlighted that major risks are spatiotemporal rain variability and rainfall shortage / excess (drought / flood), strong winds, and excessive temperature. Confronted with these hazards, local farmers are developing on their own endogenous strategies, which are mostly not rational and far from solving climatic hazards in a sustainable way. More detailed studies are needed in order to identify together with these communities pragmatic and sustainable adaptive options. [less ▲]

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See detailPerformance assessment of the FAO AquaCrop model for irrigated cabbage on farmer plots in a semi-arid environment
Wellens, Joost ULiege; Raes, Dirk; Traore, Farid ULiege et al

in Agricultural Water Management (2013), 127

Small-scale irrigation initiatives are expanding rapidly in Burkina Faso. However, in many cases optimal yields are not being obtained despite the available water and the required nutrient applications ... [more ▼]

Small-scale irrigation initiatives are expanding rapidly in Burkina Faso. However, in many cases optimal yields are not being obtained despite the available water and the required nutrient applications. Local stakeholders need an easy-to-use decision-support tool to assess irrigation water use and its impact on yield. In this study, a water-driven crop model, AquaCrop, developed by FAO, was adapted for cabbage (Brassica oleracea L.) using a limited dataset and leave-one-out cross-validation (LOOCV). The experiment was conducted in south-western Burkina Faso on small irrigated farmer plots, where optimal managerial conditions could not always be guaranteed. Statistical indicators – normalized root mean square error (nRMSE) and index of agreement (d) – suggested that the model is very reliable for simulating cabbage biomass yield and soil water content (low nRMSE and d-index near 1). The relationship between observed and simulated yield produced a d-index of 0.99 and an nRMSE of 1.39% (or 0.59 ton/ha). The comparison between observed and modeled soil water content gave a d-index of 0.90 and an nRMSE of 4.38% (or 9.13 mm). Also of interest was the indirect link between plant density and yield via maximum canopy cover, which can considerably simplify yield estimation. It was concluded that AquaCrop was a very useful tool for enabling local end-users to evaluate and optimize cabbage yield and irrigation water use. [less ▲]

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See detailEVALUATION DES EMISSIONS DE METHANE IMPUTABLES AU SECTEUR AGRICOLE EN AFRIQUE DE L’OUEST (1961-2050)
Djaby, Bakary ULiege; Ozer, Pierre ULiege

in Boko, Michel; Vissin, Expédit W.; Afouda, Fulgence (Eds.) CLIMAT, AGRICULTURE & RESSOURCES EN EAU d'hier à demain (2013, September)

The objective of this study is to review the evolution of methane (CH4) emissions related to agriculture in West Africa over the last fifty years (1961-2010). The main agricultural sources of CH4 are ... [more ▼]

The objective of this study is to review the evolution of methane (CH4) emissions related to agriculture in West Africa over the last fifty years (1961-2010). The main agricultural sources of CH4 are ruminants (enteric fermentation) and rice production (anaerobic decomposition). To do this, we used the FAO statistics for both rice production and livestock. It appears that CH4 emissions are regionally rising although presenting large differences between the Sahelian countries and those of the Gulf of Guinea. Indeed, the countries bordering the Sahara seem to take profit of improving rainfall over the past two decades to increase livestock. On the contrary, wetter countries increase rice development. A close relationship is found between the human population and CH4 emissions from the agricultural sector. Yet, human population increase projected by 2050 is questionable, particularly in relation to the margin of CH4 emissions increase in West Africa. [less ▲]

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See detailSpatial Distribution of Calibrated WOFOST Parameters and Their Influence on the Performances of a Regional Yield Forecasting System
Djaby, Bakary ULiege; Louis, Kouadio; El Jarroudi, Moussa ULiege et al

in Sustainable Agriculture Research (2013)

We investigate in this study (i) a redefinition of crop variety zonations at a spatial scale of 10x10 km, and (ii) the influence of recalibrated crop parameters on regional yield forecasting of winter ... [more ▼]

We investigate in this study (i) a redefinition of crop variety zonations at a spatial scale of 10x10 km, and (ii) the influence of recalibrated crop parameters on regional yield forecasting of winter wheat and grain maize in western Europe. The baseline zonation and initial crop parameter set was derived from the operational European crop growth monitoring system (CGMS) which involves the agrometeorological model WOFOST. Air temperature data from 325 weather stations over the 1992-2007 period were used to define new zonations in a 300 x 300 km test site. Two parameters which influenced mostly the phenological development stages (i.e. TSUM1 and TSUM2, the effective air temperature sums from emergence to anthesis, and from anthesis to maturity, respectively) were chosen and calibrated. The CGMS was finally run based on these new recalibrated parameters and simulated crop status indicators were compared with official statistics over the 2000-2007 period. Our results showed that the days of anthesis and maturity were simulated with coefficients of determination (R2) ranging from 0.22 to 0.87 for both crops over the study site. A qualitative assessment of maximum leaf area index and harvest index also revealed a more consistent spatial pattern than the initial zonation in the simulation results. Finally, recalibrated TSUM1 and TSUM2 led to improved relationships between official yield and simulated crop indicators (significant R2 in 17 out of 28 and in 14 out of 59 NUTS3 regions with respect to the best predictor for grain maize and winter wheat, respectively). [less ▲]

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